Various motile mechanosensitive cilia will be investigated to determine whether local membrane depolarization in reaction to restrained or induced ciliary beat is a general phenomenon. Electrophysioligical techniques will be used to characterize the phenomenon in terms of specific ionic events while simultaneously correlating these events with stages of the beat cycle by visualizing individual cilia through video enhancement microscopy. Thin-section and freeze-fracture electron microscopy will be employed to determine whether motile sensory cilia have basal membrane specializations which distinguish them from somatic cilia. Using tissues having a gradient of development, the appearance of mechanosensitivity will be correlated with the possible appearance of specific membrane specializations. These approaches should lead to the mechanism and locus of transduction in mechanosensitive or true sensory cilia and, consequently, may provide a more basic understanding of the precise control of somatic ciliary beat and its coordination. The mechanical basis for ciliary metachrony is fundamental to an understanding of normal ciliary function in the respiratory system and abnormal function in the diseased state.